The present invention relates to switches and more specifically to plunger switches.
It is known in the prior art to use a toggle switch for user input devices, such as in a keyboard. Toggle switches include two parts: a top that is moveable and a bottom that is stationary. The bottom contains a circuit path that includes a break in the circuit path. The top part of the toggle switch contains a conductive element on its bottom surface, which when depressed, comes into contact with the bottom part and completes the circuit allowing a signal to pass through the circuit. Thus, the circuit path may be closed by toggling the switch. Toggle switches require mechanical contact in order to close the circuit. The disadvantage of the toggle switch is that over repeated use the contacting parts will begin to wear, and the switch will eventually fail.
It is also known in the art to use plunger type switches for switching operations. Plunger switches provide an advantage over toggle switches, because they do not require mechanical contact to close a circuit and therefore, have a longer life expectancy. Plunger switches operate using electromagnetic principles. For example, a Hall Effect plunger switch operates to create a voltage in response to a perpendicular magnetic field, thus producing an output signal.
One problem with plunger type switches that operate in an on-off configuration is that they lack tactile feedback. As a user presses on the plunger which contains a magnet and the plunger passes by a Hall-Effect sensor, there is no sensory indication to the user that the plunger has created a magnetic field and the switch has switched to or from an off-state to an on-state. The only feedback that the user may receive occurs when the plunger bottoms out and physically touches the bottom surface of the housing that holds the plunger. Thus, the plunger needs to be fully depressed for feedback, even though the switch may have changed states at other points during the depression of the plunger. For example, the switch may change states when the plunger is pressed halfway and thus, pressing the plunger the additional halfway so that the plunger contacts the bottom of the housing, wastes the user's energy and may prematurely fatigue a user who must repeatedly push the plunger switch.